KR20220085910A - Power conversion system for capacitive deionization module linked photovoltaic module, method of regenerating energy using thereof and computer readable medium - Google Patents

Abstract

The present invention relates to a photovoltaic module-linked power conversion system of a capacitive desalination module, an energy recovery method using the same, and a computer-readable recording medium. It relates to a power conversion system. A solar-linked power conversion system of a capacitive desalination module according to an embodiment of the present invention includes: a capacitive desalination (CDI) module for removing ionic substances in raw water using an electric double layer principle; a photovoltaic (PV) module for supplying power by sunlight to the capacitive desalination module; a battery for storing the power recovered from the capacitive desalination module; The DC voltage converted from the DC voltage supplied from the photovoltaic module is supplied to the capacitive desalination module during water purification, and the DC voltage converted from the DC voltage across the capacitive desalination module is stored in a battery to regenerate when water is discharged. bidirectional power conversion module; and a control module for controlling the battery, the solar module, and the bidirectional power conversion module. Through this, it can operate independently without a grid, enabling freshwater production without electricity costs.

Description

POWER CONVERSION SYSTEM FOR CAPACITIVE DEIONIZATION MODULE LINKED PHOTOVOLTAIC MODULE, METHOD OF REGENERATING ENERGY USING THEREOF AND COMPUTER READABLE MEDIUM}

The present invention relates to a photovoltaic module-linked power conversion system of a capacitive desalination module, an energy recovery method using the same, and a computer-readable recording medium. It relates to a power conversion system.

Capacitive DeIonization (CDI) is a kind of electro-adsorption technology. When an electric potential is applied to the electrode, the ionic substances move and adsorb to the electrode surface by the adsorption reaction in the electric double layer formed on the electrode surface ( ion adsorption reaction), when the adsorption capacity of the electrode reaches its limit, the electrode is regenerated by short-circuiting the charged electrode to desorb ionic materials (ion desorption reaction).

As described above, the electro-absorption technology is very easy to operate because it can absorb and desorb ions by changing only the potential of the electrode. Also, since the applied potential is operated at a low voltage where electrolysis does not occur, energy consumption is lower than that of the existing desalination process. There are features that can be significantly reduced.

However, in the existing capacitive desalination module, when the electrode is regenerated after the ionic material is adsorbed to the electrode, the charged electrode is short-circuited and consumed as thermal energy through the resistor. There is a risk of fire.

Therefore, in order to reduce overall energy consumption, it is possible to use a power conversion system in connection with renewable energy such as sunlight. However, if the capacitive desalination module is directly connected to the existing solar power conversion system, the power received from the solar module is converted to DC/DC power to match the grid and voltage level, and then DC/AC power conversion is performed again. Here, AC power is received from the grid, converted back to DC power, and DC/DC power conversion is performed again to match the electrical insulation and voltage size. The process is complicated, and there is a problem in that cost and power loss occur a lot in the process.

In addition, in the prior art, the entire system is connected to the system and the solar module, so if the system is out of power, the weather is bad or the sun does not rise, making it difficult to use the solar module, the system can no longer be used and the power environment is bad. It was difficult to use the conventional system in a country or region.

Korean Patent Application Laid-Open No. 2011-0071701 ('Electrosorption deionization device', publication date: June 29, 2011)

The present invention relates to a photovoltaic module-linked power conversion system of a capacitive desalination module for independently operating a capacitive desalination module system using a photovoltaic module and a battery charging/discharging unit without grid connection, an energy regeneration method using the same, and computer readout To provide a possible recording medium.

A solar-linked power conversion system of a capacitive desalination module according to an embodiment of the present invention includes: a capacitive desalination (CDI) module for removing ionic substances in raw water using an electric double layer principle; a photovoltaic (PV) module for supplying power by sunlight to the capacitive desalination module; a battery for storing the power recovered from the capacitive desalination module; The DC voltage converted from the DC voltage supplied from the photovoltaic module is supplied to the capacitive desalination module during water purification, and the DC voltage converted from the DC voltage across the capacitive desalination module is stored in a battery to regenerate when water is discharged. bidirectional power conversion module; and a control module for controlling the battery, the solar module, and the bidirectional power conversion module.

Bidirectional power conversion module according to an embodiment of the present invention, a DC link capacitor for storing a DC voltage to be supplied to the capacitive desalination module; a bidirectional DC/DC converter for converting the DC voltage of the DC link capacitor and a DC voltage corresponding to the capacitive desalination module; and charging and discharging the battery so that the DC voltage of the DC link capacitor is kept constant It may further include a; battery charging and discharging unit for controlling the.

In addition, the control module according to an embodiment of the present invention performs a cycle operation set to be performed continuously and alternately in a water purification mode and a water discharge mode, wherein the water purification mode includes a positive water purification mode and a negative water purification mode, , the water withdrawal mode may supply power having the same polarity as that of the water purification mode after the water purification mode.

In addition, the control module, in the water purification mode, applies the purified water power to the capacitive desalination module for a preset purified water set time (T1+T2), and in the water discharge mode, the water discharge power supply to the capacitive desalination module may be applied from the elapse of the constant set time (T1 + T2) until the polarity of the drain power supply is changed.

Specifically, the control module controls the bidirectional power conversion module in a current mode so that a constant direct current is provided to the capacitive desalination module in a water purification mode, wherein the voltage at both ends of the capacitive desalination module reaches a target voltage When it is controlled in voltage mode so that a constant DC voltage is applied to the capacitive desalination module, at this time, T1 is the period from the start of the water purification mode to the time when the voltages at both ends of the capacitive desalination module reach the target voltage, In the water withdrawal mode, the bidirectional power conversion module may be controlled in the current mode so that a constant direct current is output from the capacitive desalination module.

When the DC voltage stored in the battery according to an embodiment of the present invention is a low voltage type lower than the DC voltage of the solar module, the solar module includes a Buck MPPT converter, and the bidirectional power conversion module is insulated It may include a type high-frequency transformer.

On the other hand, when the DC voltage stored in the battery according to another embodiment of the present invention is a high voltage type higher than the DC voltage of the solar module, the solar module includes a boost MPPT converter, and the battery is charged and discharged. The unit may include a Buck-Boost converter.

In another aspect of the present invention, the energy regeneration method using the solar-linked power conversion system of the capacitive desalination module includes the above-described configuration in the solar-linked power conversion system of the capacitive desalination module, in the bidirectional power conversion module, purified water a first step of converting the DC voltage supplied from the solar module into a DC voltage in the mode and supplying it to the capacitive desalination module; and a second step of converting the DC voltage at both ends of the capacitive desalination module into a DC voltage in the bidirectional power conversion module to be regenerated into the battery in the water withdrawal mode.

Specifically, by the control module according to an embodiment of the present invention, in a positive water purification mode, charging by applying purified water power to the capacitive desalination module for a preset purified water set time (T1 + T2); reducing the target current by the control module until the polarity of the drain power supply is changed when the set time for the purified water has elapsed in the drain mode, and discharging the capacitive desalination module; charging, by the control module, in a negative water purification mode, by applying purified power to the capacitive desalination module for a preset purified water setting time (T1+T2); and by the control module, increasing the target current until the polarity of the drain power supply is changed when the water purification set time has elapsed in the drain mode, and discharging the capacitive desalination module; may include

As another aspect of the present invention, it is possible to provide a computer-readable recording medium in which a program for executing the above-described method on a computer is recorded.

According to one embodiment of the present invention, it is possible to independently operate without a grid using a solar module and a battery charging/discharging unit integrated in the capacitive desalination module, so that fresh water production is possible without electricity cost, and power using a bidirectional power conversion module The conversion process is simplified, power loss and consequent cost loss can be prevented, and environmental costs due to energy recycling can be reduced.

In addition, according to an embodiment of the present invention, energy is recovered by regenerating the DC voltage at both ends of the capacitive desalination module as an AC power source in the drain mode, and stored and utilized in the battery charging/discharging unit, thereby increasing power efficiency and power cost It has the advantage of being able to produce fresh water without

1 is a block diagram of a photovoltaic module-linked power conversion system of a capacitive desalination module according to an embodiment of the present invention.
2 is a conceptual diagram for explaining the operation of the capacitive desalination module according to an embodiment of the present invention.
3A and 3B are a system operation sequence of a capacitive desalination module including a conventional one-way power conversion module and a system operation sequence of a capacitive desalination module according to an embodiment of the present invention.
4A and 4B are block diagrams of a control module included in a solar module-linked power conversion system of a capacitive desalination module according to an embodiment of the present invention according to an embodiment of the present invention.
5 is a control mode of the capacitive desalination module according to an embodiment of the present invention, and is a waveform diagram of a water purification mode and a water discharge mode.
6 is a flowchart illustrating a control method of an energy regeneration device using a capacitive desalination module according to an embodiment of the present invention.
7A and 7B are circuit diagrams of a bidirectional power conversion module included in a photovoltaic module-linked power conversion system of a capacitive desalination module and a photovoltaic module connected thereto according to an embodiment of the present invention.
8 is a flowchart illustrating an energy regeneration method using a photovoltaic module-linked power conversion system of a capacitive desalination module according to an embodiment of the present invention.
9 is a flowchart illustrating an energy regeneration method performed by a control module in a solar module-linked power conversion system of a capacitive desalination module according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiment of the present invention may be modified in various other forms, and the scope of the present invention is not limited only to the embodiments described below. The shapes and sizes of elements in the drawings may be exaggerated for a clearer description, and elements indicated by the same reference numerals in the drawings are the same elements.

1 is a block diagram of a photovoltaic module-linked power conversion system 100 of a capacitive desalination module according to an embodiment of the present invention, and is a system-free power conversion system.

First, as shown in FIG. 1, the solar module-linked power conversion system 100 of the capacitive desalination module according to an embodiment of the present invention uses an electric double layer principle to remove ionic substances in raw water. A type desalination module (CDI, 120), a photovoltaic (PV) module 130 for supplying power by sunlight to the capacitive desalination module 120, and the power recovered from the capacitive desalination module 120 A battery 160 storing 120) a bidirectional power conversion module 110 that stores and regenerates the DC voltage converted from both ends of the DC voltage as a battery 160, and the battery 160, the solar module 130 and the bidirectional power conversion module ( The control module 140 for controlling the 110 may be included.

That is, the capacitive desalination module 120, the bidirectional power conversion module 110 for applying purified power and drain power to the capacitive desalination module 120 in order to remove ionic substances in raw water, and the capacitive desalination module during purified water A solar module 130 for supplying power by sunlight to 120, a battery 160 for storing energy regenerated from the capacitive desalination module 120 when discharged, and a solar module 130, It may include a control module 140 for controlling the battery 160 and the bidirectional power conversion module 110 .

This is a low voltage type in which the voltage across the DC link capacitor 1102 connected in parallel between the bidirectional power conversion module 110 and the solar module 130 and the battery 160 is less than 300V, and similar to the voltage of the battery 160 . It is a configuration diagram when maintained in a range.

In this case, the MPPT of the solar module 130 may use a Buck-type converter, and the bidirectional power conversion module 110 may use a high-frequency transformer.

The solar module-linked power conversion system 100 of the capacitive desalination module according to another embodiment of the present invention is connected in parallel between the bidirectional power conversion module 110 and the solar module 130 and the battery 160 When the voltage across both ends of the DC link capacitor 1102 is a high voltage of 300V or more, the battery charging/discharging unit 150 for controlling the charging and discharging of the battery 160 may be further included.

That is, the bidirectional power conversion module 110 includes a DC link capacitor 1102 that stores a DC voltage to be supplied to the capacitive desalination module, a DC voltage of the DC link capacitor 1102, and the capacitive desalination module ( A battery charging/discharging unit including a bidirectional DC/DC converter 1101 for converting a DC voltage corresponding to 120), and controlling the charging and discharging of the battery so that the DC voltage of the DC link capacitor 1102 is kept constant. 150) may be further included.

In the case of the low pressure type, the DC voltage of the photovoltaic module 130 and the capacitive desalination module 120 can be directly stored in the battery 160 by stepping down, but in the case of the high voltage type, it cannot be directly stored in the battery, so the solar module 130 and the DC voltage of the capacitive desalination module 120 may be boosted, stored in the DC link capacitor 1102 , and then transferred to the battery 160 through the battery charging/discharging unit 150 .

At this time, the MPPT of the solar module 130 may boost the voltage provided to the solar module 130 by using a boost-type converter, and the battery charging/discharging unit 150 is a buck-boost (Buck-) Boost) converter can be used to control charging and discharging of the battery 160 .

In particular, according to the embodiments of the present invention, since there is no system, the above-described bidirectional power conversion module 110 does not need to convert the DC voltage of both ends of the capacitive desalination module 120 into an AC voltage in the draining mode, and the corresponding DC It may be converted into voltage and stored in the battery 160 .

In addition, the bi-directional power conversion module 110 receives a DC voltage from the solar module 130 and the battery 160 and converts it into a DC voltage corresponding to the capacitive desalination module 120 and provides it. The DC voltage converted from the DC voltage supplied from the optical module 130 is supplied to the capacitive desalination module 120, and the DC voltage at both ends of the capacitive desalination module 120 is converted into a DC voltage when the water is discharged to the battery. It may include a bidirectional DC/DC converter 1101 that regenerates to 160 .

As an embodiment, the bidirectional DC/DC converter 1101 may be designed as an isolated type or a non-isolated type.

Therefore, through the above-described configuration, the capacitive desalination module 120 performs a water purification mode and receives pre-treated raw water, adsorbs ions in the raw water, and can provide fresh water from which ions are removed. In addition, regeneration may be performed by performing a desorption mode and desorbing adsorbed ions.

Specifically, FIG. 2 is a conceptual diagram for explaining the operation of the capacitive desalination module 120 shown in FIG. 1 described above.

In the capacitive deionization module (CDI) 120 , ionic materials are moved and adsorbed to the electrode surface by an adsorption reaction in the electric double layer formed on the electrode surface when a potential is applied to the electrode, and the adsorption capacity of the electrode When this limit is reached, the electrode is regenerated by discharging the charged electrode and desorbing the ionic material.

Specifically, first, in the water purification mode, as shown in FIG. 2A , when a positive potential is applied to the positive electrode 121a and a negative potential is applied to the negative electrode 121b, the negative ions 122 in the raw water W1 are the positive electrode At 121a, the positive ions 123 in the raw water W1 are adsorbed to the negative electrode 121b (referred to as 'ion adsorption reaction').

Then, in the withdrawal mode, as shown in (b) of FIG. 2 , a negative potential is applied to the positive electrode 121a and a positive potential is applied to the negative electrode 121b, or the electrodes 121a and 121b are short-circuited. At this time, the electrode ( The ionic materials adsorbed to 121a and 121b are desorbed from the electrodes 121a and 121b (referred to as 'ion desorption reaction').

Thereafter, as shown in (c) of FIG. 2, the concentrated water W2 containing ionic substances may be discharged to the outside.

In the present invention, instead of short-circuiting the electrodes 121a and 121b during the above-described ion desorption reaction, the DC voltage generated by the charged electrodes 121a and 121b of the capacitive desalination module 120 is regenerated to the battery 160. do it with Regenerated energy can be stored and reused, maximizing energy utilization.

3A and 3B are a system operation sequence of a capacitive desalination module including a conventional one-way power conversion module and a system operation sequence of a capacitive desalination module 120 according to an embodiment of the present invention.

As shown in FIG. 3A, conventionally, a unidirectional power conversion module is used. In the conventional capacitive desalination module, after the ionic material is adsorbed to the electrode, when the electrode is regenerated, the charged electrode is short-circuited and consumed as thermal energy through the resistor. Therefore, energy cannot be recovered, and the opposite polarity has to be used alternately when performing water purification mode (adsorption process) and water withdrawal mode (desorption process). For example, a positive potential is used in the water purification mode, and a negative potential is used in the evacuation process.

At this time, if the opposite polarity is applied, since a peak current is generated and the electrode consumption is accelerated, the system including the capacitive desalination module may be damaged. The remaining charge had to be discharged.

Therefore, as shown in FIG. 3a, if the conventional capacitive desalination module performs adsorption at a potential of 300V in the water purification mode, after a short process in which the electrode is short-circuited, desorption must be performed at a potential of -300V in the water withdrawal mode. , energy was consumed in all sections.

On the other hand, as shown in FIG. 3B , an unnecessary short section may be removed in the capacitive desalination module 120 according to an embodiment of the present invention, and the draining mode may be performed immediately at the same polarity as the water purification mode. In the withdrawal mode, the electric charge charged in the electrode is discharged through the bidirectional power conversion module 110 to be sent to the battery 160 for storage, and energy generated during withdrawal is transferred back to the battery 160 through the bidirectional power conversion module 110 . ) to recover energy.

That is, through the bidirectional power conversion module 110 and the removal of the resistor that consumes regenerative energy, energy is saved in the draining process by regenerating energy, and it is possible to directly enter the draining mode from the water purification mode without a short-circuit process, so the same cycle Compared to the prior art, it is possible to repeat more water purification processes and water discharge processes, and accordingly, the water recovery rate can be increased, and the operating efficiency is superior.

In addition, by removing the short section, the water withdrawal process can be performed using a potential of the same polarity as that of the water purification process, thereby preventing re-adsorption of ions, and ions remaining at the electrode interface are adsorbed on the electrode surface without an ion exchange membrane. It is possible to prevent a decrease in the salt removal rate by preventing Since the ion exchange membrane can be eliminated, it is possible to achieve cost savings and space intensive in the CDI module. However, the claims are not limited thereto, and a capacitive desalination module 120 having an ion exchange membrane coupled electrode may be used.

Accordingly, according to an embodiment of the present invention, the control module 140 performs a cycle operation set so that the water purification mode and the water discharge mode are continuously and alternately performed, and the water purification mode is a positive water purification mode and a negative water purification mode. It includes a water purification mode, and the drain mode may supply power having the same polarity as that of the water purification mode after the water purification mode.

4A and 4B are block diagrams of the control module 140 included in the solar module 130-linked power conversion system of the capacitive desalination module 120 according to an embodiment of the present invention. to be. 4A is a block diagram of the control module 140 when the voltage across the DC link capacitor 1102 is 300V or more of a high-voltage type, and FIG. 4B is a low-voltage control module in which the voltage across the DC link capacitor 1102 is less than 300V ( 140) is a block diagram.

As shown in Fig. 4a, according to the high voltage type according to an embodiment of the present invention, the control module 140 controls the bidirectional power conversion module 110, the solar module 130 and the battery charging/discharging unit 150, Specifically, controlling the bidirectional power conversion module 110 may mean controlling the bidirectional DC/DC converter 1101 .

Specifically, according to an embodiment of the present invention, the bidirectional power conversion module 110 is supplied to the DC link capacitor 1102 from the solar module 130 and the battery 160 or the battery charging/discharging unit 150 . A bidirectional DC/DC converter 1101 that converts the DC voltage Vdc and the DC voltage Vdc of the DC link capacitor 1102 into a DC voltage Vo corresponding to the capacitive desalination module 120. In the water purification mode, the purified power supplied from the photovoltaic module 130 or the battery 160 is supplied to the capacitive desalination module 120, and in the drain mode, direct current from both ends of the capacitive desalination module 120 The drained power converted from a voltage to a DC voltage may be regenerated and stored in the battery 160 .

Alternatively, as shown in FIG. 4B , according to the low voltage type according to an embodiment of the present invention, the control module 140 may control the bidirectional power conversion module 110 and the solar module 130 . Specifically, controlling the bidirectional power conversion module 110 may mean controlling the bidirectional DC/DC converter 1101 , which is the same as the high voltage type described above.

In the case of the low-voltage type, the DC voltage at both ends of the capacitive desalination module 120 can be converted into a DC voltage and stored in the drain mode without performing separate control on the battery 160 .

That is, the bidirectional DC/DC converter 1101 converts the voltage Vdc across the DC link capacitor 1102 to the load voltage or output voltage Vo and the load corresponding to the capacitive desalination module 120 according to an embodiment of the present invention. It serves to supply by converting it into current or output current (Io).

According to the high-pressure type according to an embodiment of the present invention, the control module 140 may be configured as shown in FIG. 4A .

Specifically, the control module 140 is configured to calculate the current command value (Ipv*) having the maximum power, the actual voltage and actual current measurement value (Vpv, Vpv, Ipv), the current command value Ipv* can be calculated. The MPPT module 401 is a module for performing a Maximum Power Point Tracking (MPPT) algorithm, and may use a method for tracking maximum power, such as a Perturb and Observe (P&O) method, and is not limited thereto.

The solar module 130 may include a solar panel and an MPPT charger (MPPT CHARGER), as shown in FIG. 4A .

Thereafter, the error calculator 402 may calculate an error between the command current Ipv* output from the MPPT module 401 and the actual current measured value Ipv.

The PI controller 403 can control the current magnitude of the active power by the error output from the error calculator 402, and generates a switching signal for controlling the duty (Dmin, Dmax) through the current control to generate a DC PWM The switch on/off time may be adjusted by causing the generator 404 to generate a corresponding waveform.

In addition, as shown in FIG. 4A, in relation to the bidirectional DC/DC converter 1101, the mode selector 410 includes a command value Vo* of the output voltage output from the error calculator 411 and the actual output voltage ( Vo) and the command value (Io*) and the actual output current (Io) of the output current output from the error calculator 412 are received and the difference between the command value (Vo*) of the output voltage and the actual output voltage (Vo) You can choose a mode according to the relationship. That is, the control module 140 may select the CC mode and the CV mode and change the command value according to the command value Vo* of the output voltage and the actual output voltage Vo.

In addition, the PI controller 413 generates a switching signal for controlling the duty ratio by controlling the voltage or current according to the mode determined by the mode selector 410, and is described later through the DC PWM generator 414 provided with this. It is possible to output voltage and current waveforms as shown in FIG. 5 .

Meanwhile, as shown in FIG. 4A , in the case of a high voltage type, the battery charging/discharging unit 150 is separately required to constantly maintain the voltage Vdc applied to both ends of the DC link capacitor 1101 . The control module 140 is the battery charging/discharging unit 150, the PI controller 406 is the command value (Vdc*) of the DC voltage stored in the DC link capacitor 1102 output from the error calculator 405 and the actual DC voltage ( Vdc) may be input and the effective battery current magnitude (Ibat ^* ) may be output.

In addition, the error calculator 407 calculates an error between the effective battery current magnitude Ibat ^* output from the PI controller 406 and the actual battery current Ibat, and the PI controller 408 calculates the effective current magnitude by the error. The duty (Dmin, Dmax) can be obtained by controlling it.

At this time, the duty range (Dmin, Dmax) limits the output of the PI controller 408 to Dmax or less so that the battery 160 does not reach the maximum low pressure and switch to the CV mode or deviate from the rated power of the battery 160 It can be obtained by passing the limiter 409a. By passing this, the DC PWM generator 424 generates a corresponding waveform within the rated range of the battery 160 to obtain a switching waveform according to the on-off switch.

Meanwhile, according to the low-pressure type according to an embodiment of the present invention, the control module 140 may be configured as shown in FIG. 4B .

Specifically, the control module 140 calculates the current command value (Ibat*) having the maximum power, from the actual voltage and actual current measurement values (Vpv, Ipv) of the solar module input through the MPPT module 401 Current command value Ibat* can be calculated. The MPPT module 401 is a module for performing a Maximum Power Point Tracking (MPPT) algorithm, and may use a method for tracking maximum power, such as a Perturb and Observe (P&O) method, and is not limited thereto.

The solar module 130 may include a solar panel and an MPPT charger (MPPT CHARGER), as shown in FIG. 4B .

The current command value Ibat* is provided to the battery 160, and the error calculator 402 calculates an error between the battery current command value Ibat* output from the MPPT module 401 and the actual current measurement value Ibat. can

Thereafter, the PI controller 403 can control the current magnitude of the active power by the error output from the error calculator 402, and a switching signal for generating the duty (Dmin, Dmax) is generated through the current control. The DC PWM generator 404 generates a waveform according to it so that the switch on/off time can be adjusted accordingly.

At this time, the duty range (Dmin, Dmax) limits the current output from the PI controller 403 so that the battery 160 does not reach the maximum low pressure and switch to the CV mode or deviate from the rated power of the battery 160. Limiter 409b ) passed and then transferred to the DC PWM generator 404 to generate a corresponding waveform within the rated range of the battery 160 .

The control module 140 related to the bidirectional DC/DC converter 1101 is the same as shown in FIG. ) is not controlled.

5 is a control mode of the capacitive desalination module according to an embodiment of the present invention, and is a waveform diagram of a water purification mode and a water discharge mode according to the operation of the capacitive desalination module 120, and the above-described bidirectional DC/DC converter 1101 ) shows the control mode of the related control module 140 in detail.

As shown in FIG. 5 , the control mode according to the embodiment of the present invention may be controlled by being divided into a current mode (CC) and a voltage mode (CV).

When the actual output voltage (Vo) is less than the output voltage command value (Vo*), it operates in the constant current mode (CC mode), and when the actual output voltage (Vo) is greater than the output voltage command value (Vo*), the constant voltage mode (CV mode) ) can be driven.

As shown in FIG. 5 , the T1 section is operated in the CC mode, charging is performed as current is supplied, and when the output voltage Vo gradually increases to reach the maximum value Vo_max, the CC mode is switched to the CV mode.

In addition, the T2 section is operated in the CV mode, ions are adsorbed, and the ion concentration adsorbed to the electrode gradually decreases over time, so that the output current Io is gradually reduced. At this time, the T1+T2 total time can be set as an integer time, and T1 is automatically determined as the time to access the CV mode, not the set value.

After the T1+T2 time, which is the constant setting time, it is set to change from water purification operation to drain operation, and it is converted from CV mode to CC mode again, and the output current command value (Io*) is gradually decreased to -Io_max. At this time, as the output current Io is discharged in the opposite direction, the output voltage Vo gradually decreases, and when the output voltage Vo falls below 0v after the time T3 elapses, the operation is changed to the integer operation again. That is, the T3 time is a value that is automatically determined as soon as the output voltage becomes 0v as the water withdrawal period.

Accordingly, time T1 is CC(+) mode, time T2 is CV mode, time T3 is CC(-) mode, time T1+T2 is a constant operation mode, and time T3 is a water drain operation mode.

That is, according to an embodiment of the present invention, it can be seen that the product of voltage and current in the discharge section becomes negative (-), which indicates that the power flows in the opposite direction (that is, energy is recovered to the battery 160) and energy is supplied. Able to know. And it can be seen that there is no current peak in the transient state between all transitions, and the transition is made smoothly.

However, according to an embodiment of the present invention, when the output voltage Vo rushes to a negative voltage below 0v in the CC(-) mode, the current and the voltage have the same polarity, and the integer operation may be performed again. Since the negative integer process also has a similar and symmetrical structure to the above-described positive integer process, further description is omitted to avoid duplication.

Therefore, according to an embodiment of the present invention, in the water purification mode, the purified water power is applied to the capacitive desalination module for a preset purified water set time (T1+T2), and in the water discharge mode, the capacitive desalination module The drain power may be applied (T3) from the elapse of the constant set time (T1 + T2) until the polarity of the drain power is changed.

At this time, the control module 140 controls the bidirectional power conversion module 110 in the current mode (CC(+)) so that a constant direct current is provided to the capacitive desalination module 120 in the water purification mode, When the voltage Vo at both ends of the capacitive desalination module 120 reaches the target voltage Vo*, it is controlled in the voltage mode (CV) so that a constant DC voltage is applied to the capacitive desalination module 120, at this time , T1 is a period from the start of the water purification mode to the time when the voltages at both ends of the capacitive desalination module 120 reach the target voltage.

In addition, in the water withdrawal mode, the bidirectional power conversion module 110 may be controlled in a current mode (CC(-)) so that a constant DC current is output from the capacitive desalination module 120 .

6 is a flowchart illustrating a control method of an energy regeneration device using the capacitive desalination module 120 according to an embodiment of the present invention according to FIG. 5 described above.

As shown in FIG. 6 , the constant set time T1+T2 is a set value set by the user. If the charging time exceeds T1+T2 (No in S601), the output current command value (Io*) is set to Io_max. is gradually increased (S602), and when T1+T2 is exceeded (Yes in S601), the output current command value Io* is decreased (S603). At this time, when T1+T2 is exceeded, the positive integer mode (charging mode) is terminated, and the output current command value Io* can be reduced to -Io_max.

As the output current command value (Io*) decreases and the current is discharged in the opposite direction, the output voltage (Vo) decreases together. ends, and a negative integer mode (negative charging mode) begins. If the output voltage Vo does not fall below 0v (NO in S604), it returns to S603, and the output current command value Io* is gradually decreased (S603), and the output voltage Vo is checked.

When the negative water purification mode (negative charging mode) is started, it can be operated in the negative water purification mode for the water purification time T1+T2. Therefore, if the charging time exceeds T1+T2 (No in S605), the output current command value Io* is gradually reduced to -Io_max (S606), and when the charging time exceeds T1+T2 (S605) , yes), the output current command value Io* is increased (S607). At this time, when T1+T2 is exceeded, the negative integer mode (charging mode) is terminated, and the output current command value Io* can be increased up to Io_max.

The output current command value (Io*) increases and the output voltage (Vo) increases together. At this time, when the output voltage (Vo) increases to 0v or more (Yes in S608), the water withdrawal mode (discharge mode) is terminated again, and the positive of the water purification mode (negative charging mode) is started (S601). If the output voltage Vo does not increase to more than 0v (NO in S608), return to S607, gradually increase the output current command value Io* (S607), and check the output voltage Vo .

That is, the positive charge mode and the negative charge mode operate in integer mode for T1+T2 time, and until T1+T2 elapses and the polarity of the output voltage changes, as the discharge mode, it can be operated in drain mode for T3 time. .

Therefore, in the energy regenerative method using the solar module-linked power conversion system of the capacitive desalination module according to an embodiment of the present invention, in the positive water purification mode, the purified water power is preset to the capacitive desalination module 120 . In the first step of charging by applying for the water purification time (T1+T2), in the drain mode, when the set time (T1+T2) has elapsed, the target current (Io*) is reduced until the polarity of the drain power is changed In the second step of discharging the capacitive desalination module 120, in a negative water purification mode, purified power is applied to the capacitive desalination module 120 for a preset purified water set time (T1 + T2) and charged In the third step and drain mode, when the constant set time (T1 + T2) has elapsed, the target current (Io*) is increased until the polarity of the drain power source is changed, and the capacitive desalination module 120 is A fourth step of discharging may be included, and the first to fourth steps may be repeated as a cycle.

At this time, in the first step, before the preset constant set time (T1 + T2) elapses, the target current is increased, and in the third step, before the preset constant set time (T1 + T2) elapses, It is possible to reduce the target current.

7 is a bidirectional power conversion module 110 included in the photovoltaic module-linked power conversion system 100 of the capacitive desalination module according to an embodiment of the present invention, and the photovoltaic module 130 and the battery 160 connected thereto. is the circuit diagram of

In particular, FIG. 7A is a circuit diagram when the voltage across the DC link capacitor 1102 connected in parallel between the bidirectional power conversion module 110 and the solar module 130 and the battery 160 is 300V or more and is a high voltage type, FIG. 7b is a circuit diagram when the voltage across both ends of the bidirectional power conversion module 110 and the DC link capacitor 1102 connected in parallel between the photovoltaic module 130 and the battery 160 is less than 300V and is a low voltage type.

The above-described bi-directional power conversion module 110 supplies purified power obtained by converting the DC voltage supplied from the solar module 130 into DC voltage to the capacitive desalination module 120 in the water purification mode, and in the water discharge mode, the capacitive type The drain power obtained by converting the DC voltage at both ends of the desalination module 120 into a DC voltage may be stored in the battery 160 to be regenerated.

First, a circuit diagram in the case of a high voltage type will be described.

Specifically, as shown in Figure 7a, the bidirectional power conversion module 110 is a full-bridge structure including first legs (T3, B3) and second legs (T4, B4) connected in parallel, the first leg ( T3 and B3 are composed of a third upper switch T3 and a third lower switch B3 connected in series, and the second legs T4 and B4 are connected in series with a fourth upper switch T4 and a fourth lower switch ( B4), and in order to remove residual ions attached to the capacitive desalination module 120 in the evacuation mode, the polarity of the DC voltage of the DC link capacitor 1102 is converted and provided to the capacitive desalination module 120 have.

On the other hand, an undescribed inductor (L) disposed between the bidirectional power conversion module 110 and the capacitive desalination module 120 boosts the voltage of the capacitive desalination module 120 to provide the DC link capacitor 1102. can

In addition, an L-C filter composed of an inductor (L) and a capacitor (C) may be further disposed between the bidirectional power conversion module 110 and the capacitive desalination module 120 , and CT2 flows into the capacitive desalination module 120 . A current sensor that measures the current Io may be connected.

In addition, the above-described solar module 130 includes a boost converter in the high voltage type, boosts the voltage (Vpv) of the solar module 130 and supplies it to the DC link capacitor 1102, bidirectional When the power conversion module 110 supplies purified power to the capacitive desalination module 120 in the water purification mode, the boosted voltage of the solar module may be provided to the capacitive desalination module 120 .

As shown in Figure 7a, the photovoltaic module 130 is a diode (D1), the first lower switch (B1) connected in series with the diode (D1), and charging power while the first lower switch (B1) is on It is a step-up converter including an inductor that boosts the voltage of the solar module 130, and through this, the boosted voltage can be provided to the capacitive desalination module 120 so that the bidirectional power conversion module 110 and grid connection are possible. have.

In addition, the battery charging/discharging unit 150 for controlling the battery 160 included in the high-voltage type when the bidirectional power conversion module 110 regenerates the drained power in the draining mode, the battery charging/discharging unit 150 is the battery 160 ) can store the drain power.

7A, the battery charging/discharging unit 150 includes a second upper switch T2, a second lower switch B2 connected in series with the second upper switch T2, and an inductor buck-boost ( Buck Boost) converter.

Hereinafter, a circuit diagram in the case of the low-pressure type will be described.

In the case of the low-pressure type, since the reduced voltage of the solar module 130 or the drained power recovered by the bidirectional power conversion module 110 can be directly stored in the battery 160, a separate battery charging/discharging unit 150 can be omitted. .

Specifically, as shown in FIG. 7B , the bidirectional DC/DC converter 1101 of the bidirectional power conversion module 110 includes a high-frequency transformer 712 for insulation and a primary-side voltage Vpri of the high-frequency transformer 712 for insulation. ) may be configured to include a first module 711 for forming, and a second module 713 for forming a secondary-side voltage (Vsec) of the high-frequency transformer 712 for insulation. Through this, it is possible to convert the high voltage of the capacitive desalination module 120 to match the voltage Vbat of the battery 160 .

The first module 711 has a full-bridge structure including a first leg (T3, B3) and a second leg (T4, B4) connected in parallel, the first leg (T3, B3) is a third upper switch (T3, B3) connected in series ( T3) and a third lower switch B3, and the second legs T4 and B4 may be formed of a fourth upper switch T4 and a fourth lower switch B4 connected in series.

The second module 713 has a full-bridge structure including a third leg (T5, B5) and a fourth leg (T6, B6) connected in parallel, and the third leg (T5, B5) is a fifth upper switch connected in series ( T5) and a fifth lower switch B5, and the fourth legs T6 and B6 may be composed of a sixth upper switch T6 and a sixth lower switch B6 connected in series.

Therefore, the high-frequency transformer 712 for insulation converts the voltage received from the capacitive desalination module 120 to the second module 713 to match the DC voltage Vbat applied across the battery 160 to the first module 711 . ) can be passed as

In addition, as shown in FIG. 7B , the above-described solar module 130 includes a buck converter in the low voltage type, and reduces the voltage (Vpv) of the solar module 130 to reduce the DC link capacitor ( 1102) and can supply a DC voltage (Vdc) to the battery.

As described above, according to one embodiment of the present invention, it is possible to increase the reliability of the system and save the overall system price by using the solar system integrated in the capacitive desalination module, and the capacitive desalination module through a single control module By controlling the solar module and the bi-directional power conversion module associated with the power conversion process, it is possible to prevent power loss and consequent cost loss, and reduce environmental costs due to energy recycling.

In particular, since it can be independently driven through the solar module 130 and the battery 160 without a grid, fresh water production is possible without electricity costs through ESS operation.

In addition, according to one embodiment of the present invention, there is an advantage in that the power efficiency can be increased by converting the DC voltage at both ends of the capacitive desalination module into an AC voltage in the water discharge mode and regenerating it into an AC power source to recover energy.

On the other hand, Figure 8 and Figure 9 is a flowchart illustrating an energy regeneration method using a solar module-linked power conversion system of the capacitive desalination module according to an embodiment of the present invention.

Hereinafter, an energy regeneration method using the solar module-linked power conversion system of the capacitive desalination module will be described with reference to FIGS. 1 to 9 . However, for the sake of simplification of the invention, descriptions of overlapping parts with respect to FIGS. 1 to 7 will be omitted.

1 to 7, the energy regeneration method using the solar module-linked power conversion system of the capacitive desalination module according to an embodiment of the present invention,

In the bidirectional power conversion module 110, it may be initiated by converting the DC voltage supplied from the solar module 130 in the water purification mode and supplying it to the capacitive desalination module 120 (S801).

At this time, the DC/DC converted voltage applied from the solar module 130 may be provided to the DC link capacitor 320 to be supplied to the capacitive desalination module 120 .

Next, the bidirectional power conversion module 110 may convert the DC voltage across both ends of the capacitive desalination module 120 in the drain mode, store it in the battery 160 and regenerate it (S802).

At this time, in the positive water purification mode, the control module 140 may charge the capacitive desalination module by applying purified power for a preset purified water set time (T1+T2) (S901). In addition, in the water discharge mode, when the set time for the water purification has elapsed, the target current is reduced until the polarity of the water discharge power source is changed, and the capacitive desalination module can be discharged (S902).

In addition, in the negative water purification mode, the control module 140 may be charged by applying purified power to the capacitive desalination module for a preset purified water set time (T1+T2) (S903). In addition, in the water drain mode, when the water purification time has elapsed, the target current is increased until the polarity of the water drain power source is changed, and the capacitive desalination module can be discharged (S904).

As described above, according to an embodiment of the present invention, by controlling the photovoltaic module and the bidirectional power conversion module of the capacitive desalination module through a single control module 140, communication abnormality is prevented, and the reliability of the system is increased , it is possible to increase control responsiveness by preventing a delay between signals.

In addition, according to one embodiment of the present invention, by using the solar module integrated in the capacitive desalination module, the reliability of the system can be increased and the overall system price can be saved, and the power conversion process is simplified so that the power loss and consequent cost loss can be prevented, and environmental costs due to energy recycling can be reduced.

In particular, since it can be independently driven through the solar module 130 and the battery 160 without a grid, fresh water production is possible without electricity costs through ESS operation.

In addition, according to one embodiment of the present invention, there is an advantage in that the power efficiency can be increased by converting the DC voltage at both ends of the capacitive desalination module into an AC voltage in the water discharge mode and regenerating it into an AC power source to recover energy.

The energy regeneration method using the solar module-linked power conversion system of the capacitive desalination module according to the embodiment of the present invention described above may be produced as a program to be executed in a computer and stored in a computer-readable recording medium. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, and the like. In addition, the computer-readable recording medium is distributed in a computer system connected to a network, so that the computer-readable code can be stored and executed in a distributed manner. And a functional program, code, and code segments for implementing the method can be easily inferred by programmers in the art to which the present invention pertains.

In addition, in describing the present invention, a 'control module' is used in various ways, for example, a processor, program instructions executed by the processor, a software module, a microcode, a computer program product, a logic circuit, an application-specific integrated circuit, firmware and the like can be implemented.

The present invention is not limited by the above-described embodiments and the accompanying drawings. It is intended to limit the scope of rights by the appended claims, and it is to those of ordinary skill in the art that various types of substitutions, modifications and changes can be made without departing from the technical spirit of the present invention described in the claims. it will be self-evident

10: AC power, 110: bidirectional power conversion module
120: CDI module, 121a: positive electrode
121b: negative electrode, 122: negative ion
123: positive ion, 130: solar module
140: control module, 150: battery charging and discharging unit
160: battery
401: MPPT module, 402: error calculator
403: PI controller, 404: DC PWM generator
405: error calculator, 406: PI controller
407: error calculator, 408: PI controller
409, 409b: limiter, 410: mode selector
411, 412: error calculator, 413: PI controller
414: DC PWM generator, 424: DC PWM generator
711: first module, 712: high-frequency transformer for insulation
713: second module
1101: bidirectional DC/DC converter 1102: DC link capacitor;

Claims (10)

Capacitive desalination (CDI) module for removing ionic substances in raw water using the electric double layer principle;
a photovoltaic (PV) module for supplying power by sunlight to the capacitive desalination module;
a battery for storing the power recovered from the capacitive desalination module;
The DC voltage converted from the DC voltage supplied from the photovoltaic module is supplied to the capacitive desalination module during water purification, and the DC voltage converted from the DC voltage across the capacitive desalination module is stored in a battery and regenerated when water is discharged. bidirectional power conversion module; and
A control module for controlling the battery, the solar module, and the bidirectional power conversion module; Containing,
Solar-linked power conversion system of capacitive desalination module. The method of claim 1,
The bidirectional power conversion module,
a DC link capacitor for storing a DC voltage to be supplied to the capacitive desalination module; Includes; a bidirectional DC/DC converter for converting the DC voltage of the DC link capacitor and the DC voltage corresponding to the capacitive desalination module;
A battery charging/discharging unit for controlling charging and discharging of the battery so that the DC voltage of the DC link capacitor is maintained constant; further comprising,
Solar-linked power conversion system of capacitive desalination module. According to claim 1,
The control module performs a cycle operation set so that the water purification mode and the water discharge mode are continuously and alternately performed,
The integer mode includes a positive integer mode and a negative integer mode,
The water withdrawal mode supplies power of the same polarity as the water purification mode after the water purification mode,
Solar-linked power conversion system of capacitive desalination module. 4. The method of claim 3,
The control module is
In the water purification mode, the water purification power is applied to the capacitive desalination module for a preset water purification time (T1 + T2),
In the drain mode, the drain power is applied to the capacitive desalination module from the elapse of the constant set time (T1 + T2) until the polarity of the drain power is changed,
Solar-linked power conversion system of capacitive desalination module. 5. The method of claim 4,
The control module is
In the water purification mode, the bidirectional power conversion module is controlled in the current mode so that a constant DC current is provided to the capacitive desalination module, and when the voltage at both ends of the capacitive desalination module reaches a target voltage, the capacitive desalination module is constant The voltage mode is controlled so that a DC voltage is applied, and at this time, T1 is the period from the start of the water purification mode to the time when the voltages at both ends of the capacitive desalination module reach the target voltage,
Controlling the bidirectional power conversion module in a current mode so that a constant direct current is output from the capacitive desalination module in the water withdrawal mode,
Solar-linked power conversion system of capacitive desalination module. According to claim 1,
When the DC voltage stored in the battery is a low voltage type lower than the DC voltage of the solar module,
The solar module includes a Buck MPPT converter,
The bidirectional power conversion module includes an isolated high-frequency transformer,
Solar-linked power conversion system of capacitive desalination module. 3. The method of claim 2,
When the DC voltage stored in the battery is a high voltage type higher than the DC voltage of the solar module,
The solar module includes a boost MPPT converter,
The battery charging and discharging unit includes a buck-boost (Buck-Boost) converter,
Solar-linked power conversion system of capacitive desalination module. Capacitive desalination (CDI) module for removing ionic substances in raw water using the electric double layer principle; a photovoltaic (PV) module for supplying power by sunlight to the capacitive desalination module; a battery for storing the power recovered from the capacitive desalination module; The DC voltage converted from the DC voltage supplied from the photovoltaic module is supplied to the capacitive desalination module during water purification, and the DC voltage converted from the DC voltage across the capacitive desalination module is stored in a battery and regenerated when water is discharged. bidirectional power conversion module; and a control module for controlling the battery, the photovoltaic module, and the bidirectional power conversion module;
In the bidirectional power conversion module, a first step of converting the DC voltage supplied from the solar module into a DC voltage in a water purification mode and supplying it to the capacitive desalination module; and
a second step of converting the DC voltage across both ends of the capacitive desalination module into a DC voltage in the bidirectional power conversion module to regenerate it into the battery;
Including, an energy regeneration method using a solar-linked power conversion system of a capacitive desalination module. 9. The method of claim 8,
charging, by the control module, in a positive water purification mode, by applying purified power to the capacitive desalination module for a preset purified water set time (T1+T2);
reducing the target current by the control module until the polarity of the drain power supply is changed when the set time for the purified water has elapsed in the drain mode, and discharging the capacitive desalination module;
charging, by the control module, by applying purified power to the capacitive desalination module for a preset purified water set time (T1+T2) in a negative water purification mode; and
increasing the target current by the control module until the polarity of the drain power source is changed when the water purification time has elapsed in the drain mode, and discharging the capacitive desalination module;
Containing, energy regeneration method using a solar-linked power conversion system of the capacitive desalination module. A computer-readable recording medium in which a program for executing the method of claim 8 or 9 on a computer is recorded.

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